Revert "trying to add first CI and docker image building"

This reverts commit 4f87fd0b

.gitlab-ci.yml

-variables:
-  # all submodules will be cloned recursively upon start of CI job
-  GIT_SUBMODULE_STRATEGY: recursive
-  GIT_SSL_NO_VERIFY: "true"
-
-stages:
-  - build
-
-##########################
-# BUILD stage            #                                
-##########################
-
-build_image:
-  # description: triggers a build of the project as a Docker image,
-  #              each branch will have an individual Docker image that will be used
-  #              in the following stages of the pipeline for testing the code
-  stage: build
-  tags:
-    - docker-image-build
-  script:
-    - ignore

Dockerfile

-# The release set in this Dockerfile defines the release of the whole project
-# and is parsed by every setup script and by the installation instructions.
-# Be aware of this effect if you edit the release here!
-FROM atlas/atlas_external_cvmfs
-ADD . /calypso
-WORKDIR /build
-RUN setupATLAS && \
-    asetup master,latest,Athena && \
-    cmake -DCMAKE_INSTALL_PREFIX=../run ../calypso && \
-    make
-